Merrill e



M. E. CLARK.'

.STABILIZERFOR AEROPLANES. APPLLCATIONl FILED FEB. I8. 1914.'

vPatentedAug. 29,1916.'

3 SHEETS-SHEET v 'R1/eww' STABILIZER FOR AEROPLANES.

APPLlcAlvoN FILED FEB. la. 1'914.

Pat-@MA1 Aug. 29, 1916.

3 SHEETS-5125er 2.y

UM vez/'Chti I M. E. CLARK..

STABFLZER FOR AVEROPLANES, APPLICATION FILED FEB. I8. {i914- 3 SHEETS-SHEET 3f n 41 f1rnted Aug. '29, 19161 sTATEsPA- OFFICE.

MERRILL n. CLARK, or New Yoan, N. Y,

STABILIZEE FOR AEBOPLANES.

Specification of Letters Patent.

Patented Aug. 29, 191.6.

Application filed February 18,` 1914. Serial No. 819,356.

To all 'whom t may concern.'

Be it known that I, MERRILL E. CLARK,

, a citizen ofthe United States, residing at New York, in the county and-State of New' York, have invented a new and useful Improvement in Stabilizers for Aeroplanes, of l which the following, taken in connection with the accompanying drawings, is a specication. l

-`The'present invention involves primarily the .nstruction of improved stabilizing devices adapted for application to any of the usiial types of craft designed for aerial navigationi; such devices are disclosed in the ,present4 instance as applied to the type commercially known as a monoplane, but it will be apparent that it is equally applicable to any and all of the other types of aerial craft, such as biplanes, hydroplanes, etc.

The invention contemplates broadly the provision of means, brought into operation at the will of the operator, for resisting any tendency of the machine, while in fiight,.to plunge, or to tilt about a horizontal axis transverse to the line of flight, and furthermore, the provision of means, brought into action either automatically or at the will of the operator, for resistingany tendency of the machine while .in flight, to tilt about an axis substantially vparallel to the' line of flight. By the coperation of the instrumentalities above referred to, which are particularly described hereinafter in connection with the accompanying drawings, the dangers resulting from cross currents and rapidly varying conditions of atmospheric pressure, as met with in practical aerial l navigation, are eectually eliminated.

. Referring to the accompanying drawings, Figure 1 is a side view of an aeroplane equipped with myv invention. Fig. 2 isa plan view. Fig. 3 is an enlarged side view `o f. the forward portion of the-aeroplane,

' certain parts thereof being shown in central vertical section for the sakel of clearness. Fig. 4 is a. side elevation, partly in section, of the apparatus for effecting the automatic operation of a portion of the stabilizing device. Fig. 5 is a section on line 5 5, Fig. 4. Fig. 6 is a fragmentary sectional'view of parts shown in Fig. 5. Fig. 7 is a plan view of a portion of the apparatus shown in mechanism on line 11--1l, Fig. 10.

Similar reference characters refer to similar parts in the different views. v Referring particularly to Figs. 1, 2 and 3, the aeroplane, in the present instance of the monoplane type, comprises a suitably shaped covered framework from which extend the usual suitably curved sustainin planes 1, 1, and which carries the usual alighting and starting gear 2, 2', guiding tail 3, motor 4 and propeller 5, all of which are well known to those skilled in the art, andv which form no part of .my present invention. Inl the forward end ofthe machine, between the motor 4 anda cock pit in which is locateda seat 6 for the operator, a vertical mast 7, made hollow forfa purpose to be hereinafter` described, and extending4 well above the covered framework, is rotatably mounted. The mast 7 Yis journaled in an upper bearing 8 carried by the framework, and a smaller tubular member 9 telescoped with said mast and forming an extension of the same, is

supported in a thrust bearing 10, which is preferably integral with a lower .guy wireI post 11 carried by the framework. At its `upper end the mast 7 has secured thereto by any suitable means, a vertically disposed stabilizing vane 12, which, in the normal Hight of the machine lies substantially in the vertical plane ofthe line of flight, but

which is adapted to be rocked about a vertical axis under certain conditions by the mechanism about to be described.l Suitably supported by means of a cradle 13 connecting transverse members A, A, of the frame rearwardly of the mast 7, is a horizontally disposed cylinder 13, Figs. 3, 4, 5 and 7, having its axis transverse to the axis of the aeroplane. The cylinder 13 Ais closedl at its ends, and Contains a piston 14, which has a ported in brackets 35,

piston rod 15 extendedthrough a suitable stuing box 16 carried by one of the heads of the cylinder 13, which rod 15 is supported, near its extreme outer en d, 1n a guide aperture formed in the vertical end 17 of the bracket 17, extending from the cylinder 13. The bracket 17 carries a pm 18 which engages a recess or keyway 19 formed in the rod 15, thereby permitting longitudinal, but preventing rotary movement of said rod. The rod 15 is provided on either side of the vertical support 17 of the bracket with a fixed collar 20, and between each of said collars and the support 17 the rod 15 carries a coiled spring 21, said springs being equal in length and of the same strength, whereby to maintain the piston 14 in a. position approximately midway the length of the cylinder 13. The framework of the aeroplane carries a tank 22 containing compressed air, from which a feed pipe 23 leads to the devices which depend on this medium for their actuation. A branch pipe 24 conveys compressed air from the feed pipe 23 to a horizontal pipe 25 beneath the cylinder 13, Fig. 4, the ends of the pipe 25 opening into oppositely disposed threeway valve casings 26, Fig. 6, each of which has exhaust ports I27, opening to the at mosphere, and cylinder ports 28, which are connected by short lengths ofpipe 29 with the interior of cylinder 13, onop'posite sides of the piston 14. Each valve casing 26 contains a plug valve 30 provided with a passage 31, which in the position of the valves shown in Fig. 6 connects the compressed air supply with each end of the cylinder` 13, thereby maintaining equal pressures on each side of the, piston 14, to retain the same in its position midway the length of the cylinder. Each plug valve 30 is provided with a stem 32, extending outwardly therefrom through its'respective casing, and to each of said stems 32 is secured a depending arm 33, apertured at its lower end to form guiding and supporting means for a horizontal bar 34 extended through said apertures. Sup- Fig. 5, depending from the transverse members A, A, is a spindle 36 from which is suspended a freely swinging pendulum 37. The pivotal portion of the spindle 36 is constructed to present two opposed rounded shoulders 38 to the opposite faces of the arm of the pendulum, which faces are correspondingly rouned off from the aperture in said arm, as'at 39, 39, so as to permit of a'universal movement of the pendulum about its pivotal point. The upper-end of the pendulum arm is expanded into a wide fork 40, embracing the bar 34 and maintained in fixed longitudinal relation thereto by a pair of spaced rods 41 extending'transversely7 of said bar 34 in -the same horizontal plane, between which,

rods the fork 40 is slidingly held. Immediately outside the guide apertures in the depending arms 33 the bar 34 has secured thereto fixed collars 42, which engage with the arms to rotate one or the other of the plug valves 30 upon longitudinal movement of thebar under the influence of the pendulum 37, as hereinafter described.

The operation of the above described mechanism is as follows r-In the flight of the machine, as long as it maintains its normal upright position, the relation of the several parts of the mechanism is as shown in Figs. 4, 5, 6 and 7. However, if from any cause the machine tips 'sidewise, about an axis parallel to the line of Hight, the influence of the pendulum 37, which is adapted to remain always, by reason of its suspension, in a perpendicular position, brings into action instrumentalities which effect a rotation of the mast 7, and with it the vane 12, in a direction to cause said vane to present a surface in opposition to the resistance of the air in order to right the machine, in the following manner.

Considering Fig. 4, which presents mechanism lying in a substantially vertical plane, transverse to the machine and to 'the line of flight thereof, assume that the machine tilts sidewise to lower the parts at the right hand end of Fig. 4 and to raise those at the left hand end. The pendulum 37, however, remains perpendicular, whereby the engagement of lts upper forked end 40 with the rods 41 moves the bar 34 to the left. The right hand collar 42 on the bar engages the arm 33 of the right hand valve 30 to move the latter in a clockwise direction, causing the passage 31 of said valve to connect the cylinder port 28 of the right hand valve casing 26 with the exhaust port 27, thereof. The left hand valve 30 on the other hand is not actuated by this movement of the bar 34 to the left, since the said bar will merely move through the guide aperture in the depending arm 33 of said valve. The connection thus established between the right hand end of the cylinder and the exhaust port 27 permits the escape of compressed air from said end of the cylinder, whereby the piston 14 moves to the right, by reason of the predominating pressure on its left hand side.

The piston rod 15 has secured thereto a collar carrying an upwardly projecting pin 43. The mast 7 carrying the vane 12 is surrounded by a sleeve 44, which is prevented fromy moving thereon by a pin 45, Fig. 7; and a lever 46 is hinged to said sleeve as at 47, extending rearwardly of the machine and provided with a slot 48 through which the pin 43 is adapted to project. Itwill be seen that the movement of the piston to the right, as above described, eiiects, through the piston rod 15, pin 43 and lever 46, a rotation of the mast 7 and vane 12 to the left, or in a counterclockwise direction, looking down on the machine, whereby the vane 12 is caused to present a surface which will be acted upon by the resistance of the atmosphere to the forward movement of the machine, to restore the machine to .its normal vertical position'. The righting of the machine as above described, causes the .operating devices of the stabilizer vane 12 to resume the Vpositions indicated in. Figs. 4, 5, 6 and 7; the pressure previously prevailing in the right hand end of the cylinder 13 is restored, and the piston 14 again moves back to its normal position midway the length of the cylinder owing to the said restoration of pressure and also to the action of the equalizing springs 21, 21. It will be apparent of course, that a tilting'of the machine in the other direction will actuate the left hand valve in Fig. 4, causing a movement of the piston 14 to the left, and a swinging of the mast 7 and vane 12 in the opposite direction from that previously described, to effect the righting of the machine. Y

It will be noted that the pendulum 37 is so suspended that it will perform its function without binding on its pivot, when the aeroplane is pointed upward or downward. Furthermore, the shape-oi` the port openings 27 and 28 of the valve casings and of the passages 31 in the valves is such that a slight movement of the valve cuts olf the supply of compressed air from the corresponding end of the cylinder and almost simultaneously connects such end with the atmosphere, and even though the machine tips excessively, causing relatively great movement of the valve, the connection between the Vcylinder and atmosphere is maintained. f

The above desirable operation is e'ec by extending each cylinder port 28 circumferentially of the valve casing as at 28 toward the exhaust port; by correspondingly recessing the adjacent end ofthe valve pas- A so' sages as at 31';- and by elongating the exhaust ports as at 27. means of the hinged connectionA of the lever 46 with the sleeve 44, it is ossible if desired, to disconnect the mast and^thevane 12 from -the automatic operating mechanism, and rotate the same in either direction by hand, the lever 46 being extended rear-- wardly of the piston rod 15, 1n close proxf imity to the operator, for this purpose.

- Figs.' 3, 8, 9, 10 and 11 illustrate the other elements of the improved stabilizing means, which are designed to'resist and correct sudden plunging of the machine, about a horizontal'ais transverse to the Vline 'of' Bight.

Furthermore, by A travel.

The pin. 45, Figs. 3 and 7, previously referred to, passes through a' 'member 49, which is carried within the telescoped end portion of the member 9 of the hollow mast, and which serves as the head of a cylinder 50 formed byl said hollow mast, the other head of said cylinder being formed by member 51, which is provided with a stuiing box of the usual type for the passage of a piston rod52, carried by a reciprocating piston 53 Within the cylinder 50. The piston rod passes loosely through a guide 54 carried at the extreme upper end of the mast 7 and is loosely embraced thereabove by a hub 55,

Figs. 3 and 9, carrying oppositely extending i armsv56. The endl of the'piston rod 52 is surmountedby a head 57 to whichare pivotally attached a pair of tubes 58, and a pair of tubes 59 are pivotally attached to the' upper end of the mast 7, the tubes 58 and 59 lying in the same plane as the arms 56. To the outer ends of each arm 56 are pivotally attache-d a pair of rods 60, which are adapted to telescope into the respective tubes 58 and 59, as clearly shown in Fig.'9. Attachedto the tubes 58 and 59 is a silk or canvas vane 61 which is held in its extended and ,taut position in a vertical plane at right angles to the plane of the 'vane 12, when its vframework is in the position shown in Fig. 9, the piston 53 at such time being `at the extreme upper limit of its movement in the cylinder 50, as shown in Fig. 3. When thepiston 53 led upward, as shown'in Fig. 3, and connected to onev of the ports 63 of a fourway val'vecasing 64, shown in section in Fig. 10, which is mounted in convenient reachof the operator. The said valve casing V64 is secured to said mast by pi 65- and 66, which are Aconnected to openings 67 and 68 respectively `of said valve casing, and which communicate at their other ends with the interior of the cylinder- 50, beyond-the upper and lower limits, respectively, o' piston Seated within t e valve casing 64 is a plug valve 69,' having a pair of curved passages therethrough; the one 70, adapted to connect ports 68 and 63 when the valve is turned by a handle' 7 1 .into the positionl shown in Fig. 10 to elevate the piston53 .and distend the vanel 61, and the other passage 72, when the valve is in this position, adapted toconnectjjhe port 67, in connection with the upper enf/lof the cylinder' 50, with a' port 73 in the valve-casing. Theport 7 3'/is in vco1url munication `with al substantially /c'yhnwhich bore forms a seat for a reciprocating valve 75, norma'lly held in the full line position shown in Fig. 11, by a spring 76, but'- adapted to assume the dotted line position of said ligure when a button 77 on the outer end thereofis pressed inwardly. The bore 74: has a recess 78 in its wall, leading inwardly from the port 73, and diametrically opposite said port 73 and the'inner end of said recess 7 8 the bore is provided with ports 79 and 80 respectively, the onel 79, leading to the atmosphere, and theother, 80, in connection with a pipe SlYleading to a small closed tank 82 preferably mounted adjacent the air supply tank 22, as shown in Fig. 3. The valve 75 has a diametrical passage 83 connecting ports 73 and 79 in the normal position of the valve. rThe passage 83 is provided at its end adjacent the port 79 with a longitudinal extension 84 which is long enough to conneet the ports 79 and 80 when the valve is in normal position. The coperation of the two valves 69 and 75 in controlling the movement of thevane 61 is as follows z-t will be noted the two valves can be operated simultaneously, the thumb of the hand which is used to turn the handle 7l being employed to depress the button 77. rlhe upward movement of the piston 58 to extend the vane 61 is accomplished by rocking the valve 69 to bring its passages into the position shown in Fig. 10, with the air supply pipe 62 in connection with the pipe 66 leading tothe cylinder 50 below piston 53,

and with the pipe 65, from above said piston connected with the exhaust passage 73 leading to the open lair at 79 when the 4plug 75 is held out by spring 76 as shown in Fig. 11.

This operation extends the vane to its fullv height. if, however, the plug 75 be pushed in against the tension of the spring 76 when air is to be exhausted from above or below the piston 53, the passage 83 through the plug will be carried out of register with the opening 79 and brought in'to register with the pipe 81 leading to the closed air tank 82. The volume o f the pipe 8l and tank 82 is equal tothe volume of the cylinder 50 in whichthe'f''piston moves. Air will, therefore, iiowfron one side of the piston 53 into the tank 82 until the piston has as sumed a l substantiallyfmidw'ay position in the cylinder, whereupon 'the air pressure will. become equalized on each side of the piston, bringing the latter to a state of rest, andI holding the vane 61 half extended. When it is desired to lower the vane, the valve 69 is turned in the opposite direction, to connect ports 63 and 67 by means of valve passage' 72, and ports 68 'and 73 by means of the.

valve passage 70, thereby admitting air above the piston 53 and exhausting airfrom below said piston. -V Y i the movement of the valve 69, the vane 6l 4 may be made to assume any desired position intermediate its extreme open and closed positions, whereby the resistance exerted against plunging of the machine may be varied at will. The provision of the two stabilizing vanes actuated as above described greatly minimizes the dangers incident vto both endwise and sidewise tipping of the aeroplane; and the utilization of compressed air as a medium for actuatingthe said devices insures the certain and instantaneous action so greatly to be desired in the operation of safety ldevices on-aeroplanes.A It is to be understood that in the normal iight of the machine, the vane 61 is carried in its collapsed position above the vane 12; the mechanism for distending the vane 61 is only brought into o eration when the aeroplane exhibits a ten ency to plunge;

l claim,' Y

l. In an aeroplane, a hollow Amast extending perpendicularly upward above the framework, a vane xed to said mast, normally disposed in the axis of the line of flight of 4the machine, a collapsible vane adapted to lie, when distended, in a plane at right angles to the plane of the first vane, means/carried within said mast for controlling the distention of said collapsiblel vane, means for admitting pressure fluid on yopposite sides of said member to control the position of`said second vane, a cylinder, a piston within said cylinder having a connection with said mast, andmeans, responsive to sidewise tipping of the machine, for admitting pressure Huid on opposite side of said piston to rotate said mast.

3. In an aeroplane, a pair ofstabilizing vanes normally disposed in' planes intersecting at right angles, automatic means for changing the angular disposition of one of said vanes with respect to the line of flight of the machine, and iuid preure operated means for collapsing and distending the other vane.

Q4, Inan aeroplane, a collapsible vane, a double-acting pressure operated devicey for causing the collapse and the distention of said vane, a valveA controllingthe opera'v tion of said device, and a1 second valve supplementing the 'action of said first valve, for varying the amount of distention of said van@ I Y 5. In an aeroplane, a\collapsible vane, a A equalizing the pressure on opposite sides of double-acting pressure operated device for said device when said vane is partially colcausing the collapse and distention of said lapsed.

vane, means for producing a preponderance I v MERRILL E. CLARK. 5 of pressure on either side of said device to Witnesses: J

effect the complete collapse or the complete PENELOPE COMBERBACH,

distention of said vane, and means for NELLIE WHALEN. 

